when i calculate a liquid-gas flow, i have to add different forces on the bubbles when they are at different positions. how can i do that?

some one told me that the buoyant force of the bubbles under a sloped static solid wall could be represented by imposing the horizontal gravity acceleration conponent on the plane directly under the wall, but i still don't know how to add the gravity acceleration component on a given plane, it seemed that only in the "operating conditions window" that the gravity acceleration can be defined, by it is refer to the whole system,not to a fixed plane. would you please tell me how to do with these problems?

thanks!

Maybe you can do it by defining in the Boundary conditions, under Momentum - the wall velocity or forces acting on the wall. Check it out, might help.

but it doesn't do. i should add the force on the discrete phase, not the continuous, there are no way to add different force to the bubbles when they are at different positions, right?

Maybe there is, by using a UDF. Maybe read abuot UDFs and their use for this purpose. I think it is applicable.

thanks!using udfs is a way to go,but i still don't know how to add different force on the same bubble with udf when the bubble was at the different positions .

Hello I am not clear with forces?? Are they the Drag , lift so on. They can be done in the interactions panel if thats what u are looking for! Podila

it might help, i'll try, thanks a lot.